Gonadotropin-releasing hormone neurons and pathways in the brain of the female mink (Mustela vison)

Abstract

The distribution of gonadotropin-releasing hormone-immunoreactive neurons and processes was mapped in the female mink brain using coronal, horizontal and sagittal sections. Perikarya were found along a ventral continuum including the olfactory tubercle, the diagonal band of Broca, the lateral septum, the preoptic and anterior hypothalamic area and the mediobasal hypothalamus; 80% of the perikarya were counted in the mediobasal hypothalamus. Fibres were mainly observed in the organum vasculosum of the lamina terminalis and the median eminence. A few processes terminated in the ependymal cells lining the third and lateral ventricles. The total number of immunoreactive perikarya was the highest in the brains of females sacrificed in July; it then significantly decreased until December. This variation is discussed in relation to the annual breeding cycle.

Estrogen receptor and progesterone receptor-immunoreactive cells are not co-localized with gonadotropin-releasing hormone in the brain of the female mink ( Mustela vison )

“…As steroid receptor immunoreactivity was restricted to the nucleus and GnRH localized in the cytoplasm, the immunocytochemical approach used made it possible to easily detect a nucleus labelled by the bluish-black nickel-enhanced DAB reaction product within a cytoplasm with a reddish-brown staining. The distribution of GnRH-IR neurons observed here was identical to that previously reported using the same antibody (NToumi et al 1992). GnRH perikarya extended from the olfactory tubercule to the infundibular area of the hypothalamus.…”

“…Neurons immunoreactive for GnRH were observed along a rostrocaudal continuum from the olfactory tubercule to the mediobasal hypothalamus as previously reported in this species using the same antibody (NToumi et al 1992). Immunoreactivity for GnRH was not altered by the double-staining procedure.…”

“…Ovulation is induced by mating. One striking characteristic of this species is the major concentration of GnRH-immunoreactive (IR) perikarya in the mediobasal hypothalamus; furthermore, in the female, the number of GnRH-IR cells displays a decrease from July to December paralleling that of daylength (NToumi et al 1992). This variation may result from the feedback of ovarian steroids on the hypothalamus.…”

Socially regulated reproductive development: Analysis of GnRH‐1 and kisspeptin neuronal systems in cooperatively breeding naked mole‐rats (Heterocephalus glaber)

“…A similar distribution is seen in Natal, Cape, and Cape Dune mole‐rats (Oosthuizen et al, ; Hart et al, ) and in ferrets, rhesus monkeys, and humans (Anthony et al, ). In Damaraland, Highveld, and common mole‐rats and in rats, mice, minks, ewes, and springboks these processes are more profuse in the external zone (Anthony et al, ; Lehman et al, ; Toumi et al, ; Silverman et al, ; Robinson et al, ; Molteno et al, ; Du Toit et al, ; Herbison, ). In contrast, they are found predominantly in the internal zone in bats (Anthony et al, ; Fernandez et al, ).…”

Analysis of gonadotrophin‐releasing hormone‐1 and kisspeptin neuronal systems in the nonphotoregulated seasonally breeding eastern rock elephant‐shrew (Elephantulus myurus)

“…However, in common mole‐rats ( Cryptomys hottentotus ) and Cape dune mole‐rats ( Bathyergus suillus ), equivalent proportions are found in those rostral sites and in the mediobasal hypothalamic regions (Du Toit et al, ; Hart et al, ). In mink ( Mustela vison ), in contrast, ~80% of the GnRH‐1‐ir cell bodies complete their migration in the mediobasal hypothalamus (Toumi, Martinet, & Peytevin, ), which is also the location for most of these cell bodies in humans, monkeys, bats, and ferrets (King & Anthony, ; King, Anthony, Fitzgerald, & Stopa, ).…”