Omneity® Pellets
All-In-One Vitamin & Mineral Pellet
Topic:Pituitary
The pituitary gland in horses is a small, yet significant endocrine organ located at the base of the brain. It is responsible for producing and releasing hormones that regulate various physiological processes, including growth, metabolism, and reproduction. The gland is divided into two main parts: the anterior pituitary, which secretes hormones such as adrenocorticotropic hormone (ACTH) and growth hormone (GH), and the posterior pituitary, which releases hormones like vasopressin and oxytocin. Changes or dysfunctions in pituitary function can lead to conditions such as pituitary pars intermedia dysfunction (PPID), commonly known as equine Cushing's disease, which affects older horses. This page compiles peer-reviewed research studies and scholarly articles that explore the structure, function, and clinical implications of the pituitary gland in equine health.
Isolation and amino acid sequence of the alpha-subunit of follicle-stimulating hormone from equine pituitary glands. Six hundred milligrams of follicle-stimulating hormone (FSH), containing 110 NIH-FSH-S1 units/mg, was isolated from 9 kg of equine pituitary glands. The equine FSH was dissociated into alpha- and beta-subunits. A tentative amino acid sequence of the alpha-subunit was determined. The alpha-subunit contained 82 amino acids. The equine FSH-alpha is shorter by 10 to 14 amino acids at the NH2 terminus and has several substitutions at several positions as compared with human FSH-alpha and bovine thyroid-stimulating hormone-alpha. At the intraspecies level, the alpha-subunits of human FSH, human lute...
Disseminated septic meningitis in a mare. Physical, neurologic, and clinicopathologic findings in a 3-year-old female Morgan horse with anorexia and nasal discharge suggested suppurative meningitis. Necropsy findings substantiated the tentative diagnosis. Actinomyces sp was cultured from a meningeal abscess surrounding the pituitary gland and from resolving lung abscesses.
Induction of ovulation and multiple ovulations in seasonally anovulatory and ovulatory mares with an equine pituitary extract. A crude equine pituitary ethanol extract (EE) was used to induce single and miltiple ovulations in seasonally anovulatory pony mares 3-15 years of age. 12 mares were injected daily for 14 days with EE; 6 of the EE-treated mares were also treated with human chorionic gonadotropin (HCG), and 6 control mares received saline vehicle only. In a 2nd experiment designed to determine if EE treatment could induce multiple ovulations in seasonally ovulatory mares, 7 mares were treated during diestrus, 7 mares were treated beginning on Day 1 of estrus, and 7 remained untreated. The results of experiment ...
Studies on metabolism and effects of estrogen on pituitary prolactin and LH secretion. The effect of a subcutaneous injection of estradiol on the secretion of pituitary prolactin in the rat and the relationship between serum estradiol level and luteinizing hormone (LH) secretion in mare were reviewed. In addition, the effect of estradiol injection on LH secretion and the metabolism of [14C] estradiol in intact and bile duct fistulated pony mares were studied. Low (0.1 mug/day/rat) to moderate dose (5 mug/day/rat) of estradiol benzoate injected subcutaneously to mature or immature rats significantly increased pituitary content of prolactin and serum prolactin level five- to tenfo...
Luteolysis with prostaglandin F2alpha or an antiserum against an equine pituitary fraction in hysterectomized mares. Luteolysis, determined by corpus luteum weight and progesterone concentration in jugular blood, occurred in uterine-intact and in hysterectomized mares after injection of prostaglandin F2alpha or of an antiserum against an equine pituitary fraction. Results indicated that luteolytic effects of exogenous prostaglandin F2alpha and inhibition of the endogenous luteotrophic activity of the hypophysis (pituitary gland) by antiserum did not involve the uterus.
The cycle of oestrus, ovulation and plasma levels of hormones in the mare. The duration of the oestrous cycle and day of ovulation were recorded in six mares which were used for concurrent assay of plasma levels of sex steroids and pituitary LH concentration. Peak of progesterone were reached during dioestrus and those of oestradiol and androstenedione occurred 2 days before ovulation and were in decline on the day of ovulation. Plasma oestrone remained constant (between 9 and 12 pg/ml) throughout the cycle. Plasma LH rose to a maximum near to the time of ovulation, and thereafter decreased gradually until mid-dioestrus. The pattern of secretion is compared with that...
Duration of oestrus and time of ovulation in mares treated with synthetic Gn-RH (AY-24,031). Synthetic Gn-RH, administered during oestrus, stimulates the release of pituitary LH in the cyclic mare. Duration of oestrus was significantly reduced by 1 mg Gn-RH given on Day 2 of oestrus; the time of ovulation, measured in days from the onset of oestrus, also tended to be reduced. An injection of 2 mg Gn-RH had nor further effect, but daily injections from Day 2 until ovulation significantly shortened the duration of oestrus and the time to ovulation. The profiles of LH were found to be variable from mare to mare, but in all mares, treated and control, elevation of LH was detected close to...
Ovarian changes during early pregnancy in pony mares in relation to PMSG production. The ovaries of twenty pregnant mares were examined daily, per rectum, for the first 4 months of gestation and note was made of their estimated size and follicular content. Serial blood samples from sixteen of the mares were assayed for PMSG. A marked seasonal effect was noted on ovarian size, follicular content and ovulation rate during pregnancy but there was no such effect on PMSG production. It is concluded that PMSG is synergistic with gonadotrophins of pituitary origin and that the latter hormone are the primary stimulus on the ovary of the pregnant horse.
Development of pituitary and adrenal glands in the fetal horse. The various cell types in the adult anterior pituitary may be distinguished at the ultrastructural level of the sizes of the secretory granules within the cytoplasm. In the fetal adenohypophysis, with the exception of prolactin-producing cells, all types may be identified after Day 100 of gestation. Morphological evidence suggests that they are producing and secreting trophic hormones. The three constituent layers of the adrenal cortex are also discernible by Day 100 of pregnancy. The cells of the zona glomerulosa have large numbers of darkly stained inclusions within the cytoplasm. The zona f...
[Interstitial cell adenoma of the hypophysis with Cushing-like symptomatology in the horse]. A trabecular adenoma of the pars intermedia of the hypophysis was seen in a 13-year-old half-bred mare that presented symptoms corresponding to Cushing's disease of man. The spindle-shaped tumor cells were for the most part ‘light’, seldom ‘dark’. Both of them were characterized by well-developed rough endoplasmic reticulum, small Golgi apparatus, and typical secretory granules with a diameter of about 200 μm. The pituitary tumor and the symptoms were accompanied by increased plasma adenocorticotrophic hormone (ACTH) and by bilateral hyperplasia of the adrenal cortex. The tumor cells ...
Preparation and properties of growth hormone from equine pituitary glands. Equine growth hormone has been prepared from acetone-dried residues following extraction of gonadotropins from fresh frozen equine pituitary glands. The growth hormone appeared as a single fraction by gel filtration on Sephadex G-50 and ultracentrifugation. A sedimentation constant of 3.12 was obtained. Preliminary end-group analysis suggested phenylalanine at both aminoand carboxy-terminals. Amino acid analysis of the growth hormone was performed. Four components of equine growth hormone were separated by polyacrylamide column electrophoresis and all 4 were shown to contain growth hormone act...
