March 28, 2024

Reproduction and Evolution: A Fish Story With a Human Tell

Elephant sharks have unusual looks and evolutionary history, the latter of that makes them an intriguing animal design for comparing divergent advancement paths with people. Credit: Michael Baker, UC San Diego Health Sciences
Elephant sharks provide an unique viewpoint on how human beings progressed; a new research study parses some previously unexplained reproductive differences.
Scientists at University of California San Diego School of Medicine and in Japan have actually utilized an ancient fish to attract new insights about human biology and, in particular, how and why an extensively utilized medication works to terminate pregnancies (in people, not fish)..
The findings published in the February 11, 2022, online problem of ACS Pharmacology & & Translational Science.

The elephant shark (Callorhinchus milii) is an uncommon looking and uncommon animal model. Understood by several names, such as ghost shark, elephant fish and silver trumpeter, the types is discovered in waters off southern Australia. The smooth-skinned, cartilaginous fish grows to an optimum size of four feet and presents no threat to human beings. Their distinct hoe-shaped, proboscis-like snout is utilized to identify prey, primarily shellfish and bottom-dwelling invertebrates, through motion and weak electrical fields.
Its a different characteristic that makes elephant sharks appropriate for certain kinds of research study: They belong to the earliest group of jawed vertebrates and have the slowest progressing genome of all known vertebrates, which make them perfect for investigating how some biological systems have developed in bony vertebrates, consisting of humans. The most recent research study, comparing progesterone receptor (PR) activation in elephant sharks and human beings, provides insights in how steroid activation evolved in the latter, and why it works the method it does today.
Progesterone is a hormone that, in ladies, manages the menstrual cycle, preparation for conception and maintaining a pregnancy. The results of progesterone are mediated by its nuclear receptor, PR. Scientists found that PR activation in elephant sharks requires a various mix of hormonal agents and steroids than PR activation in humans, with the latter requiring less but more specific hormone and steroidal triggers..
More surprisingly, they found that RU486, a medically authorized medical compound that obstructs or ends pregnancy in people and is frequently called “the abortion tablet,” does not have the same result in elephant sharks. It does not prevent progesterone activation of elephant shark PR..
The findings, stated senior author Michael Baker, PhD, research study teacher at UC San Diego School of Medicine, light up the divergent evolutionary courses of fish and human beings, and offer insight about how other more popular animal designs, particularly zebrafish, may be problematic when attempting to parse the pathology of endocrine disruption (when natural or manmade chemicals interfere or simulate with hormonal agents that regulate development, recreation and other standard functions) or develop new drugs.
Referral: “Regulation by Progestins, Corticosteroids, and RU486 of Transcriptional Activation of Elephant Shark and Human Progesterone Receptors: An Evolutionary Perspective” by Xiaozhi Lin, Wataru Takagi, Susumu Hyodo, Shigeho Ijiri, Yoshinao Katsu and Michael E. Baker, 6 December 2021, ACS Pharmacology & & Translational Science.DOI: 10.1021/ acsptsci.1 c00191.
Co-authors include: Xiaozhi Lin, Shigeho Ijiri and Yoshinao Katsu, Hokkaido University, Japan; and Wataru Takagi and Susumu Hyodo, University of Tokyo.

The elephant shark (Callorhinchus milii) is an unusual looking and uncommon animal design. Understood by several names, such as ghost shark, elephant fish and silver trumpeter, the types is found in waters off southern Australia. The smooth-skinned, cartilaginous fish grows to an optimum size of 4 feet and positions no risk to humans.