3.1.35. Hormones involved in reproduction and their sources transaction of external signal

3.1.35. Hormones involved in reproduction and their sources transaction of external signal

The External environment where the fish is living plays vital role in inducing the animal to go for maturation. Photoperiod (the duration / or length of day time) plays important role in maturation of animals. The pineal organ through the photoreceptor cells and other environmental culs produce electrical pulse which includes the production of melatonin from Nacetyl serotomin in the presence of hydroxyindole–O-methyl transferare an enzyme. This organ in fishes mediates photoperiod control of gonadal activity, which involves the pineal hormone melat and the regulation of diurnal cycle of gonada release. Illustration

Spring spawner normally breed during the lengthier photoperiod where as the winter spawner breed during only shorter photoperiod.

Mechanism involved in maturation and ovulation

Egg development and Endocrine regulation

Steroids in the male :

  • steroid production sites
  • intestitial cells in testis – leydig cells
  • sertoli cells or cyst cells
  • seminal vescicles
  • spermatogonia

Produced steroids

  • Androgen
  • Progestins
  • Steroid conjugates

Antrogen

Testosterone, 11 oxyhydrogenated androgen 11 keto testosterone

  1. Testosterone increase spermatogenesis after spermination amount decrease
  2. 11 Ketotestosterone increase spermiation
  3. Secondary serval character regulation
  4. forms pheromones – glucuromide

Progestins

Produced in the testis 17 µ hysony 20 ß dihydro progesterons – peak occur after fertilization and before the onset of spermiation. It involves in spermiation process by conrolling ionic composition in the seminial fluid and involves in spawn behaviour of male and female.

Steroid conjugates

  • Glucuronides
  • Maximum during breeding season and found during sperroiogenesis

Glucuronidation is the process to eliminate steroids by converting into water soluble and thus more readily excretable products function as sex pheromones.

Endocrine regulation of spermatogenesis and secondary sexual characteristics

Gonadal regression

Attesia of garmetes occur if the normal levels of hormones are disturbed. Altesia is involved in the removal of unused gametes after the spawning season; any may be related to the change in hormone level after spawning.

Factors inhabiting reporduction

Last modified: Monday, 2 January 2012, 5:45 AM