Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:3.4.24.64 (MPP)
 1,876 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Deficiency in the secretion of luteinizing hormone-releasing hormone (LHRH) from the median eminence (ME) is one of the factors limiting reinitiation of estrous cycles following parturition in cows. In previous studies, administration of naloxone, an opioid receptor antagonist, to postpartum cows increased LH secretion, suggesting that endogenous opioids inhibit the secretion of LHRH. This study employs quantitative light microscopy to describe morphological changes in the distribution of immunoreactive beta-endorphin (ir-beta-END) neurons in the hypothalamus of anestrous early postpartum (EPP, days 10-16, n = 5), midpostpartum (MPP, days 33-43, n = 4) and multiparous cycling cows (CYC, months 12-14, n = 4). Cryostat sections (60 microns) of perfusion-fixed ventral diencephalon and forebrain were immunostained with anti-beta-END serum via the biotin-avidin-peroxidase method or double stained sequentially with anti-LHRH serum, then anti-beta-END serum. In all cows, beta-END immunoreactive perikarya, mostly bipolar neurons, were located in the arcuate and periarcuate nucleus (ARC), with some perikarya in the ME. Within the ARC, the percentage area immunostained for ir-beta-END was greater (p < 0.01) for the CYC than EPP cows, with MPP intermediate but not significantly different from the other groups. Consistent for all cows, the percentage area of ir-beta-END in ventral ARC regions was greater (p < 0.05) than dorsal ARC regions. Fibers from these neurons coursed into the anterior hypothalamus, preoptic area and bed nucleus of stria terminalis. Ventrally projecting fibers entered the ME forming a densely staining band within the external layer.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Distribution of beta-endorphin immunoreactivity in the arcuate nucleus and median eminence of postpartum anestrus and luteal phase cows. 143 81

Deficiency in secretion of luteinizing hormone releasing hormone (LHRH) from the median eminence (ME) is one of the factors limiting reinitiation of estrous cycles following parturition in cows. This study employs quantitative light microscopy to describe morphological changes in LHRH neurons obtained from cows at three postpartum times. Tissues were obtained from anestrous early postpartum (EPP; days 10-16, n = 5), midpostpartum (MPP; days 33-43, n = 4), and multiparous cycling (CYC; months 12-14, n = 4) cows. Following perfusion fixation, cryostat sections (60 microns) of the ventral forebrain were immunostained with anti-LHRH serum via the biotin-avidin-peroxidase method. In all cows, LHRH perikarya formed a loosely arranged continuum, extending from anterior to posterior within the diagonal band of Broca, the lateral and medical preoptic areas, and the anterior hypothalamus. Width and length of perikarya were similar between postpartum groups. The number of dendrite-like processes per neuron (p less than 0.01) and average or total length of process per neuron (p less than 0.001) were greater in the CYC than in the EPP and MPP cows. Although all groups of cows contained a spectrum of lengths of dendrite-like processes, both EPP and MPP cows obtained a greater (p less than 0.05) percentage of neurons with shorter processes and a smaller percentage of neurons with longer processes. Within the ME, the percentage area occupied by immunostained fibers was less (p less than 0.05) in EPP cows than in MPP or CYC cows.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Morphological differences among luteinizing hormone releasing hormone neurons from postpartum and estrous cycling cows. 156 5