The participation of the ovarian steroids and opioid peptides in the suppression of pulsatile LH release during acute fasting was examined in rats. Ovariectomized rats bearing silicone elastomer implants of oestradiol and/or progesterone were fasted for 48 h and subsequently blood samples were taken every 6 min for 3 h. Pulsatile LH release was suppressed after 48 h of fasting in the ovariectomized rats implanted with oestradiol but not in the oil-implanted controls. This suppression was enhanced after the administration of progesterone together with oestradiol. In a second experiment, ovariectomized rats bearing implants of oestradiol or oil were fasted for 48 h and injected s.c. (2.5 mg/kg body weight) with an opioid antagonist, naloxone hydrochloride, immediately before blood sampling. In the fasted oestradiol-treated ovariectomized rats, naloxone was able to prevent the suppression of pulsatile LH release. In the absence of oestradiol, however, naloxone was without effect on LH release in either the fasted or unfasted animals. These experiments indicate that the suppression of pulsatile LH release after 48 h of fasting is dependent upon oestradiol and that endogenous opioids are involved in the suppression.

No significant differences in patients' oral health-related QoL were observed between post-initial therapy and post-surgery intervals, although a tendency of surgery to determine an improvement in QoL was observed when compared with post-initial treatment.

The effect of food deprivation on the pulsatile release of LH was examined in the normal cycling and the ovariectomized (OVX) adult female rat. In the cycling animals, there were significant decreases in the mean plasma LH levels as well as the frequency and amplitude of the LH pulse 48 h after the onset of food deprivation. On the other hand, food deprivation for up to 72 h did not cause any changes in pulsatile LH release in the OVX animals. No difference in the changes in body weight and blood glucose concentration were found between the cycling and OVX rats throughout the period of food deprivation for up to 96 h. These findings suggest that ovarian factors play an important role in the early manifestation of the effect of food deprivation on pulsatile LH release and that metabolic changes as expressed by decreases in body weight and blood glucose level per se were not the direct causes in the decrease of LH release during the period of food deprivation.

ABSTRACT. Various canine breeds are remarkably different from each other not only in their sizes and shapes but also in behavioral traits, suggesting that some of them are under genetic control. Although dopaminergic neurotransmission system is considered to affect animal behavior, little is known about related genes in canine. Relations between specific alleles in polymorphic regions of the dopamine receptor D4 gene (DRD4) and personality or psychiatric disorders have been reported in humans, and we first found polymorphism in exon III region of the gene in 4 canine breeds. In this study we surveyed allele frequency distribution in 23 breeds including a total of 1,535 unrelated individuals. In exon III, 8 alleles including a novel allele were identified. A group of breeds in which the alleles 447b, 498 and 549 were frequent tended toward high scores in aggression-related behavioral traits than that with frequent alleles 435 and 447a. Moreover, a polymorphism based on 24 bp insertion/deletion was found in exon I region for the first time in dogs. This information may be of use for candidate gene studies of behavioral variation in dogs. KEY WORDS: canine, dopamine receptor D4 gene, exons III and I, polymorphism, variation among breeds.J. Vet. Med. Sci. 66 (7): [815][816][817][818][819][820] 2004 The dog (Canis familiaris) is one of the oldest domestic species [6]. Repeated selection for the various purposes, such as hunting, herding and guarding, has made dogs vary in size, shape and behavior. Consequently, more than 400 canine breeds currently exist, and behavioral traits as well as external morphology are different among breeds [2,9,19], suggesting that some of them are under genetic control.In humans, several candidate genes have been reported to have association between their polymorphisms and particular personality [1,8,12,17]. Dopamine receptor D4 gene (DRD4), which is one of the genes relevant to neurotransmitters, includes polymorphisms in several regions. Associations have been reported between these polymorphisms and personality or psychiatric disorders, such as 'Novelty Seeking' [1], attention deficit hyperactivity disorder (ADHD) [11] and delusional disorder [4], although a considerable number of reports found no association [3,21]. The association between DRD4 and 'Novelty Seeking' is further supported by the study that DRD4 knock-out (DRD4-/-) mice are significantly less behaviorally responsive to novelty than are DRD4+/+ wild-type mice [7], suggesting that this association may be applied to other mammalian species.We previously investigated exon III region of DRD4 in dogs, demonstrated polymorphism as observed in humans, identified 7 alleles (396, 435, 447a, 447b, 486, 498 and 549) based on the number and order of the 12 and 39 bp units, and found that allele frequencies significantly varied among 4 breeds (Beagle, Golden Retriever, Shetland Sheepdog and Shiba) [14,15]. Moreover, we also found, among species in Carnivora, only Canidae (dog, wolf, and raccoon dog) had repeat structure and/or po...

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Provoked coronary spasm predicts adverse outcome in AMI patients.

Changes in the rate of progesterone and 20\g=a\-hydroxypregn-4-en-3-one (20\g=a\-OH-P) secretion by the rat ovary during the course of lactation were investigated. The level of progesterone in the ovarian vein blood, which was very low on day 1 of lactation, increased progressively up to day 8 (355 \ g=m\ g. / 100 ml. blood), then declined to day 18 (45\m=.\5 \g=m\g./100ml.) and day 21 of lactation. A high concentration of 20\g=a\-OH-Pin blood was observed on day 1 and day 21 of lactation, but from day 4 to day 18 the secretion of this steroid was relatively low. The ratio of progesterone to 20\g=a\-OH-Pexceeded unity from day 4 to day 16, and in the middle of lactation the concentration of progesterone in ovarian venous blood was about four times greater than that of 20\g=a\-OH-P. These changes in the secretory pattern of progestins during lactation are discussed in connexion with the effects of the suckling stimulus on prolactin and gonadotrophin secretion from the anterior pituitary gland.

SUMMARY The time of initiation of copious milk secretion in the mammary glands of pregnant rats and the effects of removal of ovaries and/or placentae with foetuses on lactogenesis were investigated by measuring the lactose content of the mammary glands. In the normal pregnant rat, lactose was detected in the mammary gland on the 20th day of pregnancy, but not on the 15th. An abrupt increase in lactose content occurred on the 21st day of pregnancy. Bilateral or unilateral ovariectomy, and Caesarean section, with or without ovariectomy, performed on the 18th or 19th day of pregnancy all resulted in a marked increase in the lactose content on the 2nd day after operation. Bilateral ovariectomy caused early delivery of the young and lactose content in the gland increased further after delivery. Foetuses in the unilaterally ovariectomized rats were retained normally to term. Possible participation of placentae and foetuses in the mechanism of lactogenesis in pregnant animals by controlling the activity of the ovary is discussed.