A spermatogonium (plural: ''spermatogonia'') is an undifferentiated male

germ cell Germ or germs may refer to: Science * Germ (microorganism), an informal word for a pathogen * Germ cell, cell that gives rise to the gametes of an organism that reproduces sexually * Germ layer, a primary layer of cells that forms during embry ...

. Spermatogonia undergo

spermatogenesis Spermatogenesis is the process by which haploid spermatozoa develop from germ cells in the seminiferous tubules of the testis. This process starts with the mitotic division of the stem cells located close to the basement membrane of the tubule ...

to form mature

spermatozoa A spermatozoon (; also spelled spermatozoön; ; ) is a motile sperm cell, or moving form of the haploid cell that is the male gamete. A spermatozoon joins an ovum to form a zygote. (A zygote is a single cell, with a complete set of chromosomes, ...

in the seminiferous tubules of the testis. There are three subtypes of spermatogonia in humans: *Type A (dark) cells, with dark nuclei. These cells are reserve spermatogonial stem cells which do not usually undergo active

mitosis In cell biology, mitosis () is a part of the cell cycle in which replicated chromosomes are separated into two new nuclei. Cell division by mitosis gives rise to genetically identical cells in which the total number of chromosomes is mainta ...

. *Type A (pale) cells, with pale nuclei. These are the spermatogonial stem cells that undergo active

. These cells divide to produce Type B cells. *Type B cells, which undergo growth and become primary

spermatocyte Spermatocytes are a type of male gametocyte in animals. They derive from immature germ cells called spermatogonia. They are found in the testis, in a structure known as the seminiferous tubules. There are two types of spermatocytes, primary and s ...

Anticancer drugs

Anticancer drugs such as doxorubicin and

vincristine Vincristine, also known as leurocristine and marketed under the brand name Oncovin among others, is a chemotherapy medication used to treat a number of types of cancer. This includes acute lymphocytic leukemia, acute myeloid leukemia, Hodgkin's ...

can adversely affect male fertility by damaging the DNA of proliferative spermatogonial

stem cell In multicellular organisms, stem cells are undifferentiated or partially differentiated cells that can differentiate into various types of cells and proliferate indefinitely to produce more of the same stem cell. They are the earliest type o ...

s. Experimental exposure of rat undifferentiated spermatogonia to doxorubicin and vincristine indicated that these cells are able to respond to DNA damage by increasing their expression of

DNA repair DNA repair is a collection of processes by which a cell identifies and corrects damage to the DNA molecules that encode its genome. In human cells, both normal metabolic activities and environmental factors such as radiation can cause DNA dam ...

genes, and that this response likely partially prevents DNA break accumulation. In addition to a DNA repair response, exposure of spermatogonia to doxorubicin can also induce programmed cell death (

apoptosis Apoptosis (from grc, ἀπόπτωσις, apóptōsis, 'falling off') is a form of programmed cell death that occurs in multicellular organisms. Biochemical events lead to characteristic cell changes (morphology) and death. These changes incl ...

Additional images

File:Gray1150.png, Transverse section of a tubule of the testis of a

rat Rats are various medium-sized, long-tailed rodents. Species of rats are found throughout the order Rodentia, but stereotypical rats are found in the genus ''Rattus''. Other rat genera include ''Neotoma'' ( pack rats), ''Bandicota'' (bandicoot ...

. X 250. File:Spermatocytogenesis.png, Schematic diagram of Spermatocytogenesis Wandimu Geneti

References

Germ cells {{Cell-biology-stub