Hypothalamus

About: Hypothalamus is a research topic. Over the lifetime, 22301 publications have been published within this topic receiving 1085925 citations.

Hypothalamic-pituitary vasculature: evidence for retrograde blood flow in the pituitary stalk.

Abstract: Retrograde transport of pituitary hormones in the pituitary stalk vasculature was investigated in anesthetized male rats in which the pituitary gland was intact and in animals in which the anterior pituitary, posterior pituitary, or entire pituitary gland had been removed 30 to 60 min before use. Blood was collected for 1.5 to 2 h by free flow from a single long portal vessel through a microcannula, the tip of which was pointed toward the hypothalamus. An arterial blood sample was obtained at the end of each collection of portal blood. The concentrations (ng\ml) of LH, TSH, prolactin, ACTH, α-MSH, and vasopressin, determined by radioimmunoassay, in portal plasma from rats with intact pituitary glands were as follows: LH, 2,320 ± 874 (mean and SE); TSH, 10,180 ± 1,471; prolactin, 4,858 ± 884; ACTH, 82 ± 17.0; a-MSH, 103 ± 17.8; vasopressin, 2.4 ± 1.0. The concentrations of these hormones in arterial plasma of these rats were as follows: LH, <20; TSH, 149 ± 22; prolactin, 25 ± 5.0; ACTH, 0.36 ± 0.05; α-MSH,...

Aromatization of Androstenedione by the Anterior Hypothalamus of Adult Male and Female Rats

Abstract: Homogenates of fresh tissue from adult male and female rats were incubated with appropriate co-factors and androstenedione-3H for one hour at 37° C. Extraction and identification of reaction products demonstrated the aromatization of androstenedione to estrone by anterior hypothalamus but not by posterior hypothalamus, anterior pituitary gland or frontal cortex. This finding confirms and expands the previous preliminary report of aromatization by human fetal hypothalamus to include adults of both sexes in a second species, the rat. Further localization of this reaction is consistent with concepts derived from experimental evidence which indicate central aromatization of androgens to be involved in sexual differentiation of the brain, initiation and maintenance of sexual behavior, control of gonadotropin secretion and “peripheral conversion” of circulating androgens to estrogens. (Endocrinology 90: 295, 1972)

Developmental defects of the ventromedial hypothalamic nucleus and pituitary gonadotroph in the Ftz‐F1 disrupted mice

Abstract: Ad4BP (or SF-1) has been iden- tified as a transcription factor which regulates all the steroidogenic P450 genes in the peripheral or- gans, and is encoded by the mammalian homo- logue of Drosophila FTZ-F1 gene. mRNA coding for Ad4BP was detected in the hypothalamus and pituitary of rats by RT-PCR. Immunohistochemi- cal analyses using an antiserum to Ad4BP in the brain and pituitary revealed that the transcrip- tion factor is expressed in nuclei of the dorso- medial part of the ventromedial hypothalamus (dmVMH) and in some subpopulation of the ade- nohypophysial cells. Double immunostaining of the pituitary for Ad4BP and trophic peptide hor- mones, FSH, TSH, and ACTH, indicated a re- stricted localization of Ad4BP to the gonadotroph. Disruption of the mouse Ftz-FI gene was clarified to induce severe defects in the organization of the dmVMH and the function of the pituitary gona- dotroph. However, some of the dm VMH neurons and pituitary gonadotrophs persisted, which pro- vided a sharp contrast to complete agenesis of the peripheral steroidogenic tissues (adrenal and go- nads) in the mutant mouse. Additional abnormal- ities were seen in the ventrolateral part of VMH and dorsomedial hypothalamic nucleus, both of which do not express Ad4BP but have strong reciprocal fiber-connections with the dmVMH. Aromatase P450-containing cells in the medial preoptico-amygdaloid region, which were devoid of Ad4BP, persisted even in the brain of the gene disrupted mice. The present results clearly showed that the hypothalamic and pituitary Ad4BPs are essential to normal development of the functional VMH and gonadotroph through some mechanism distinct from that in the periph-