Growth of the rat gubernaculum in vitro and localisation of its growth centre

Clinical aspects of histological and hormonal parameters in boys with cryptorchidism

“…In particular, the inguinoscrotal migration is believed to be highly dependent on androgen stimulation of the genitofemoral nerve, which secretes calcitonin gene-related peptide to provide chemotactic directional guidance for the gubernacular expansion, growth of the cremaster muscle, and expansion of vaginal processus [91][92][93].…”

Gubernacular development in the mouse is similar to the rat and suggests that the processus vaginalis is derived from the urogenital ridge and is different from the parietal peritoneum

“…In the rat, the bilaminar cremaster sac appears quite different from the strip described in humans, but during development, the rat cremaster looks like an elongated strip that forms an almost complete sac except for an initial gap at the site of attachment of the mesorchium [17]. Also, studies show that a significant amount of the growth of the muscle comes from the growth center in the gubernacular tip, rather than from the proximal attachment to the abdominal wall [18]. Taken together, these studies suggest that the cremaster muscle is mostly derived from myogenesis within the gubernaculum itself, rather than from either the internal oblique and/or the transversus abdominis muscle.…”

Mathematical modelling of gubernaculum during inguino-scrotal migration shows limb bud characteristics

“…For example, the tip of the gubernaculum can be labelled with a lipophilic vital dye to reveal the undifferentiated mesenchymal bulb that behaves like a limb bud growth centre, or "progress zone" [3]. Indeed, the gubernacular tip of the neonatal rat can be excised and grafted just like a limb bud progress zone, consistent with it containing a growth centre [2]. In addition, the fetal mouse gubernaculum expresses Fgf10 and Hoxa10, which are 2 proteins with essential roles in the developing limb bud [4].…”

“…To reach the scrotum, the gubernaculum needs to grow in size and length with significant cellular proliferation. During outgrowth the gubernaculum has many characteristics of an embryonic limb bud, including the undifferentiated mesenchymal tip, which has some qualities similar to the "progress zone" of the limb bud [2][3][4].…”