Secretion of Luteiniz Ing Hormone and Follicle Stimulating Hormone in Intact and Ovariectomized Mares in Summer and Winter 1
نویسندگان
چکیده
Sequential samples of blood were drawn vi~ jugular catheters every 15 min for 24 h from four mares in each of five reproductive states: 1) intact anestrous mares in winter, 2) intact diestrous mares in summer, 3) intact estrous mares in summer, 4) ovariectomized mares in winter and 5) ovariectomized mares in summer. Estrous mares were sampled on d 4 or 5 of estrus and diestrous mares on d 10 or 11 of diestrus. Each sample of plasma was assessed for concentrations of luteinizing hormone (LH) and follicle stimulating hormone (FSH) in two independent radioimmunoassays. A computer program was developed that determined peak hormone concentrations based on 1) assay sensitivity, 2) assay variability and 3) repeatability of peaks in both independent assays. Peaks in LH and FSH were observed for mares in all five reproductive states, except for FSH concentrations in estrons mares. High frequency peaks of short duration were observed only in ovariectomized mares. Low frequency peaks of relatively long duration were observed in both intact and ovariectomized mares in both seasons. With the exception of estrous mares, there was variation among mares in the patterns of LH and(or) FSH within any one group; all estrous mares exhibited high, variable LH concentrations and low, constant FSH concentrations. In general, peaks in both gonadotropins occurred simultaneously. Ovariectomized mares exhibited more (I?<.05) peaks/24 h than intact mares for both gonadotropins. Ovariectomized mares also exhibited more (P<.OS) FSH peaks/24 h in summer than in winter. (
منابع مشابه
Cloning and expression of Iranian Turkmen-thoroughbred horse follicle stimulating hormone in Pichia pastoris
Background: Follicle stimulating hormone (FSH) plays an essential role in reproductive physiology and follicular development. Objective: A new variant of the equine fsh (efsh) gene was cloned, sequenced, and expressed in Pichia pastoris (P. pastoris) GS115 yeast expression system. Materials and Methods: The full-length cDNAs of the efshα and efshβ chains were amplified by reverse transcriptio...
متن کاملEffects of dihydrotestosterone benzoate administration on gonadotropin secretion in ovariectomized pony mares.
Eight long-term ovariectomized pony mares were treated with either dihydrotestosterone (DHT) benzoate (400 micrograms/kg body weight) in safflower oil or an equivalent amount of oil every other day for 21 d to determine the effects of DHT on follicle stimulating hormone (FSH) and luteinizing hormone (LH) concentrations in blood samples drawn once daily and after administration of three successi...
متن کاملSerum profiles of calcium, phosphorus, magnesium, vitamin D and parathyroid hormone in Caspian horses during different seasons
Minerals play an essential role in the normal vital process.Calcium, phosphorus and magnesium are the most abundant minerals. Vitamin D and parathyroid hormone play a key role in regulation of their homeostasis as well. The aim of this study was to evaluate calcium, phosphorus, magnesium, vitamin D and parathyroid hormone on 30 Caspian horses of Guilan Province (south of the Caspian Sea) in two...
متن کاملP-198: Utilization of Pichia Pastoris Secretion System for Expression of Equine Follicle Stimulating Hormone
Background: Equine follicle stimulating hormone (eFSH) is a pituitary heterodimeric glycoprotein consists of noncovalently linked of generic alpha subunit and a hormone specific beta subunit. The molecular weights of the subunits are similar and about 16 KD. In general, FSH plays a key role in controlling vertebrate gonadal functions. In female mammals, ovarian maturation and follicular growth ...
متن کامل